The present invention relates to medical pads, and more particularly, to dual-function pads for both controlling patient temperature and providing a patient-to-electrode interface.
Increasingly, medical pad systems are being employed to achieve thermal exchange with patients. In such systems, a fluid (e.g. air or water) is circulated through one or more pads which are contacted with a patient to effect surface-to-surface thermal energy exchange. As may be appreciated, the effectiveness of such thermal exchange is largely dependent upon the extent and intimacy of skin contact, as well as the maintenance of a desired thermal gradient across the thermal exchange region.
To date, medical thermal energy exchange pads have largely been employed to address emergency hypothermia or hyperthermia patient conditions. More recently, it has also been recognized that such medical pads may be employed in conjunction with surgical procedures where selective thermal regulation of a patient is desirable.
Many of these surgical procedures entail the utilization of external electrodes for transcutaneous electrical energy receipt/transmission. By way of example, electrodes are utilized in electrosurgical procedures, electrocardiogram (EKG) monitoring, and pacing/defibrillation therapy. In each of these applications a reliable electrode-to-patient interface is of importance.
Of note, such electrode-to-skin interfaces are often located in bodily regions where medical thermal energy exchange pad contact is also desired. As such, electrode and thermal energy exchange pad placement procedures and corresponding interconnections can become complicated. Further, the efficacy of thermal regulation can be compromised.
Accordingly, a primary objective of the present invention is to provide a medical pad that facilitates the placement and utilization of componentry for both effective patient thermal regulation and one or more external electrode-to-patient interface(s).
Another objective of the present invention is to enhance the reliability of external electrode-to-patient interfaces.
Yet a further objective of the present invention is to enhance patient comfort while providing both a thermal energy exchange and electrode interface with a patient.
The above objectives and additional advantages may be realized by the medical pad disclosed hereinbelow. The inventive pad includes a fluid containing layer for containing a thermal exchange fluid circulated therethrough, wherein the medical pad is operable for thermal exchange with a patient through a first side of the fluid containing layer. The medical pad further includes at least one external electrode interconnected to the fluid containing layer on the first side thereof. As may be appreciated, the xe2x80x9cexternal electrodexe2x80x9d may be of any type that is intended or otherwise adapted to transcutaneously receive electrical energy (e.g. for medical monitoring, therapeutic or electrosurgical purposes).
The integration of a fluid containing layer and an external electrode into the same medical pad yields a number of advantages. For example, positioning of the fluid containing layer and of the external electrode may be achieved in tandem. Additionally, skin contact can be optimized within a given area, thereby enhancing thermal regulation capabilities. Further, an integrated pad approach reduces interference between interconnected componentry associated with the electrode and fluid containing layer during set-up and use.
In this regard, the inventive medical pad may further comprise an electrical connector electrically connected to the electrode and extending through the fluid containing layer to a second side thereof. In turn, the electrical connector may be interconnected with an electrical cable for electrical signal transmission (e.g. to a monitor, etc.). In one arrangement, the electrical connector may include a port (e.g. disposed in opposing relation to the electrode) for selective interconnection/disconnection with an electrical cable. Such arrangement further facilitates pad positioning and set-up operations.
The electrical connector may be located to extend through the second side of the fluid containing layer at an exit location that provides ready-access when the pad is positioned on a patient. Relatedly, the exit location may be selected so that it is not interposed between a support surface and a patient during use. For example, in a medical pad intended for contacting the back of a prone patient facing upward, the exit location may be provided within a predetermined pad area that is located immediately adjacent to the side of a patient when utilized.
To isolate the electrical connector, an insulator should surround the electrical connector as it extends through the fluid containing layer. Such insulator may be integrally defined by a backing member comprising the medical pad. More particularly, the fluid containing layer may comprise a sheet-like member adjoined to a backing member, wherein the backing member includes integral protruding ribs and/or dimples which define fluid flow channels that extend between fluid inlet and fluid outlet ports. One or more of such dimples or ribs may be disposed to act as an insulator surrounding an for the electrical connector.
As may be appreciated, the inventive medical pad may comprise one or a plurality of different external electrodes each interconnected to the fluid circulation layer on the first side thereof. Such electrodes may be located in relation to their corresponding intended functions. By way of example, the electrode(s) may be one of a group consisting of the following:
an electrosurgical return electrode;
a defibrillation electrode;
an electrocardiogram (EKG) electrode; and,
a pacing electrode.
Each of the noted electrode types provide electrical circuit return paths from a patient to a monitor or the like. As such, a reliable electrode-to-patient interface is desirable.
For such purposes, and to further provide for high-efficiency thermal transfer with a patient, the inventive pad may comprise an adhesive surface extending over at least a portion, and preferably a major portion, of the first side of the fluid circulation layer for contact with a patient. Preferably, the adhesive surface also extends over and about at least a portion of the electrode(s) to yield a substantially continuous surface for patient contact and a reliable electrode interface. By way of example, the adhesive surface may have a peel value against the skin of a patient of at least about 10 g/in. A release liner may be provided over the adhesive surface for selective removal prior to patient use.
In a primary embodiment, the adhesive surface may be defined by a conformable layer which is both thermally and electrically conductive. Preferably, the electrode(s) is located, or captured, between the conformable layer and the fluid circulation layer, wherein a pliable laminate assembly is provided for patient engagement. To enhance electrical energy receipt, the conformable layer may advantageously cover, surround and extend laterally away from the electrode(s). Again, a conformable layer that covers a major portion, if not all, of the patient facing side of the pad is preferred.
To yield the noted conductive attributes, the conformable layer may comprise a first material suspended in a matrix defined by a second material. More particularly, the first material may comprise a conductive liquid while the second material may comprise a polymer. In one arrangement, the first and second materials are defined by a hydrogel. To enhance electrical conductivity, the conformable layer may further comprise an electrically conductive additive. By way of example, such additive may be an electrolyte that is included in a liquid solution, including magnesium chloride, sodium chloride, ammonium acetate, magnesium acetate, and magnesium sulfate.
In conjunction with the noted features, the inventive medical pad may incorporate further teachings of U.S. Pat. No. 6,197,045 entitled xe2x80x9cCOOLING/HEATING PAD AND SYSTEMxe2x80x9d, and U.S. patent application Ser. No. 09/476,850 entitled xe2x80x9cCOOLING/HEATING PAD AND SYSTEMxe2x80x9d, filed Jan. 3, 2000, each hereby incorporated by reference in its entirety.
Additional aspects and advantages of the present invention will become apparent to those skilled in the art upon consideration of the further description provided hereinbelow.